1 /* 2 ** $Id: ldo.c,v 2.108.1.3 2013/11/08 18:22:50 roberto Exp $ 3 ** Stack and Call structure of Lua 4 ** See Copyright Notice in lua.h 5 */ 6 7 8 #define ldo_c 9 #define LUA_CORE 10 11 #include <sys/lua/lua.h> 12 13 #include "lapi.h" 14 #include "ldebug.h" 15 #include "ldo.h" 16 #include "lfunc.h" 17 #include "lgc.h" 18 #include "lmem.h" 19 #include "lobject.h" 20 #include "lopcodes.h" 21 #include "lparser.h" 22 #include "lstate.h" 23 #include "lstring.h" 24 #include "ltable.h" 25 #include "ltm.h" 26 #include "lvm.h" 27 #include "lzio.h" 28 29 30 31 /* Return the number of bytes available on the stack. */ 32 #if defined (_KERNEL) && defined(__linux__) 33 #include <asm/current.h> 34 static intptr_t stack_remaining(void) { 35 intptr_t local; 36 local = (intptr_t)&local - (intptr_t)current->stack; 37 return local; 38 } 39 #elif defined (_KERNEL) && defined(__FreeBSD__) 40 #include <sys/pcpu.h> 41 static intptr_t stack_remaining(void) { 42 intptr_t local; 43 local = (intptr_t)&local - (intptr_t)curthread->td_kstack; 44 return local; 45 } 46 #else 47 static intptr_t stack_remaining(void) { 48 return INTPTR_MAX; 49 } 50 #endif 51 52 /* 53 ** {====================================================== 54 ** Error-recovery functions 55 ** ======================================================= 56 */ 57 58 /* 59 ** LUAI_THROW/LUAI_TRY define how Lua does exception handling. By 60 ** default, Lua handles errors with exceptions when compiling as 61 ** C++ code, with _longjmp/_setjmp when asked to use them, and with 62 ** longjmp/setjmp otherwise. 63 */ 64 #if !defined(LUAI_THROW) 65 66 #ifdef _KERNEL 67 68 #ifdef __linux__ 69 #if defined(__i386__) 70 #define JMP_BUF_CNT 6 71 #elif defined(__x86_64__) 72 #define JMP_BUF_CNT 8 73 #elif defined(__sparc__) && defined(__arch64__) 74 #define JMP_BUF_CNT 6 75 #elif defined(__powerpc__) 76 #define JMP_BUF_CNT 26 77 #elif defined(__aarch64__) 78 #define JMP_BUF_CNT 64 79 #elif defined(__arm__) 80 #define JMP_BUF_CNT 65 81 #elif defined(__mips__) 82 #define JMP_BUF_CNT 12 83 #elif defined(__s390x__) 84 #define JMP_BUF_CNT 18 85 #elif defined(__riscv) 86 #define JMP_BUF_CNT 64 87 #else 88 #define JMP_BUF_CNT 1 89 #endif 90 91 typedef struct _label_t { long long unsigned val[JMP_BUF_CNT]; } label_t; 92 93 int setjmp(label_t *) __attribute__ ((__nothrow__)); 94 extern __attribute__((noreturn)) void longjmp(label_t *); 95 96 #define LUAI_THROW(L,c) longjmp(&(c)->b) 97 #define LUAI_TRY(L,c,a) if (setjmp(&(c)->b) == 0) { a } 98 #define luai_jmpbuf label_t 99 100 /* unsupported arches will build but not be able to run lua programs */ 101 #if JMP_BUF_CNT == 1 102 int setjmp (label_t *buf) { 103 return 1; 104 } 105 106 void longjmp (label_t * buf) { 107 for (;;); 108 } 109 #endif 110 #else 111 #define LUAI_THROW(L,c) longjmp((c)->b, 1) 112 #define LUAI_TRY(L,c,a) if (setjmp((c)->b) == 0) { a } 113 #define luai_jmpbuf jmp_buf 114 #endif 115 116 #else /* _KERNEL */ 117 118 #if defined(__cplusplus) && !defined(LUA_USE_LONGJMP) 119 /* C++ exceptions */ 120 #define LUAI_THROW(L,c) throw(c) 121 #define LUAI_TRY(L,c,a) \ 122 try { a } catch(...) { if ((c)->status == 0) (c)->status = -1; } 123 #define luai_jmpbuf int /* dummy variable */ 124 125 #elif defined(LUA_USE_ULONGJMP) 126 /* in Unix, try _longjmp/_setjmp (more efficient) */ 127 #define LUAI_THROW(L,c) _longjmp((c)->b, 1) 128 #define LUAI_TRY(L,c,a) if (_setjmp((c)->b) == 0) { a } 129 #define luai_jmpbuf jmp_buf 130 131 #else 132 /* default handling with long jumps */ 133 #define LUAI_THROW(L,c) longjmp((c)->b, 1) 134 #define LUAI_TRY(L,c,a) if (setjmp((c)->b) == 0) { a } 135 #define luai_jmpbuf jmp_buf 136 137 #endif 138 139 #endif /* _KERNEL */ 140 141 #endif /* LUAI_THROW */ 142 143 144 /* chain list of long jump buffers */ 145 struct lua_longjmp { 146 struct lua_longjmp *previous; 147 luai_jmpbuf b; 148 volatile int status; /* error code */ 149 }; 150 151 152 static void seterrorobj (lua_State *L, int errcode, StkId oldtop) { 153 switch (errcode) { 154 case LUA_ERRMEM: { /* memory error? */ 155 setsvalue2s(L, oldtop, G(L)->memerrmsg); /* reuse preregistered msg. */ 156 break; 157 } 158 case LUA_ERRERR: { 159 setsvalue2s(L, oldtop, luaS_newliteral(L, "error in error handling")); 160 break; 161 } 162 default: { 163 setobjs2s(L, oldtop, L->top - 1); /* error message on current top */ 164 break; 165 } 166 } 167 L->top = oldtop + 1; 168 } 169 170 /* 171 * Silence infinite recursion warning which was added to -Wall in gcc 12.1 172 */ 173 #if defined(HAVE_INFINITE_RECURSION) 174 #pragma GCC diagnostic push 175 #pragma GCC diagnostic ignored "-Winfinite-recursion" 176 #endif 177 178 l_noret luaD_throw (lua_State *L, int errcode) { 179 if (L->errorJmp) { /* thread has an error handler? */ 180 L->errorJmp->status = errcode; /* set status */ 181 LUAI_THROW(L, L->errorJmp); /* jump to it */ 182 } 183 else { /* thread has no error handler */ 184 L->status = cast_byte(errcode); /* mark it as dead */ 185 if (G(L)->mainthread->errorJmp) { /* main thread has a handler? */ 186 setobjs2s(L, G(L)->mainthread->top++, L->top - 1); /* copy error obj. */ 187 luaD_throw(G(L)->mainthread, errcode); /* re-throw in main thread */ 188 } 189 else { /* no handler at all; abort */ 190 if (G(L)->panic) { /* panic function? */ 191 lua_unlock(L); 192 G(L)->panic(L); /* call it (last chance to jump out) */ 193 } 194 panic("no error handler"); 195 } 196 } 197 } 198 199 #if defined(HAVE_INFINITE_RECURSION) 200 #pragma GCC diagnostic pop 201 #endif 202 203 204 int luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud) { 205 unsigned short oldnCcalls = L->nCcalls; 206 struct lua_longjmp lj; 207 lj.status = LUA_OK; 208 lj.previous = L->errorJmp; /* chain new error handler */ 209 L->errorJmp = &lj; 210 LUAI_TRY(L, &lj, 211 (*f)(L, ud); 212 ); 213 L->errorJmp = lj.previous; /* restore old error handler */ 214 L->nCcalls = oldnCcalls; 215 return lj.status; 216 } 217 218 /* }====================================================== */ 219 220 221 static void correctstack (lua_State *L, TValue *oldstack) { 222 CallInfo *ci; 223 GCObject *up; 224 L->top = (L->top - oldstack) + L->stack; 225 for (up = L->openupval; up != NULL; up = up->gch.next) 226 gco2uv(up)->v = (gco2uv(up)->v - oldstack) + L->stack; 227 for (ci = L->ci; ci != NULL; ci = ci->previous) { 228 ci->top = (ci->top - oldstack) + L->stack; 229 ci->func = (ci->func - oldstack) + L->stack; 230 if (isLua(ci)) 231 ci->u.l.base = (ci->u.l.base - oldstack) + L->stack; 232 } 233 } 234 235 236 /* some space for error handling */ 237 #define ERRORSTACKSIZE (LUAI_MAXSTACK + 200) 238 239 240 void luaD_reallocstack (lua_State *L, int newsize) { 241 TValue *oldstack = L->stack; 242 int lim = L->stacksize; 243 lua_assert(newsize <= LUAI_MAXSTACK || newsize == ERRORSTACKSIZE); 244 lua_assert(L->stack_last - L->stack == L->stacksize - EXTRA_STACK); 245 luaM_reallocvector(L, L->stack, L->stacksize, newsize, TValue); 246 for (; lim < newsize; lim++) 247 setnilvalue(L->stack + lim); /* erase new segment */ 248 L->stacksize = newsize; 249 L->stack_last = L->stack + newsize - EXTRA_STACK; 250 correctstack(L, oldstack); 251 } 252 253 254 void luaD_growstack (lua_State *L, int n) { 255 int size = L->stacksize; 256 if (size > LUAI_MAXSTACK) /* error after extra size? */ 257 luaD_throw(L, LUA_ERRERR); 258 else { 259 int needed = cast_int(L->top - L->stack) + n + EXTRA_STACK; 260 int newsize = 2 * size; 261 if (newsize > LUAI_MAXSTACK) newsize = LUAI_MAXSTACK; 262 if (newsize < needed) newsize = needed; 263 if (newsize > LUAI_MAXSTACK) { /* stack overflow? */ 264 luaD_reallocstack(L, ERRORSTACKSIZE); 265 luaG_runerror(L, "stack overflow"); 266 } 267 else 268 luaD_reallocstack(L, newsize); 269 } 270 } 271 272 273 static int stackinuse (lua_State *L) { 274 CallInfo *ci; 275 StkId lim = L->top; 276 for (ci = L->ci; ci != NULL; ci = ci->previous) { 277 lua_assert(ci->top <= L->stack_last); 278 if (lim < ci->top) lim = ci->top; 279 } 280 return cast_int(lim - L->stack) + 1; /* part of stack in use */ 281 } 282 283 284 void luaD_shrinkstack (lua_State *L) { 285 int inuse = stackinuse(L); 286 int goodsize = inuse + (inuse / 8) + 2*EXTRA_STACK; 287 if (goodsize > LUAI_MAXSTACK) goodsize = LUAI_MAXSTACK; 288 if (inuse > LUAI_MAXSTACK || /* handling stack overflow? */ 289 goodsize >= L->stacksize) /* would grow instead of shrink? */ 290 condmovestack(L); /* don't change stack (change only for debugging) */ 291 else 292 luaD_reallocstack(L, goodsize); /* shrink it */ 293 } 294 295 296 void luaD_hook (lua_State *L, int event, int line) { 297 lua_Hook hook = L->hook; 298 if (hook && L->allowhook) { 299 CallInfo *ci = L->ci; 300 ptrdiff_t top = savestack(L, L->top); 301 ptrdiff_t ci_top = savestack(L, ci->top); 302 lua_Debug ar; 303 ar.event = event; 304 ar.currentline = line; 305 ar.i_ci = ci; 306 luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */ 307 ci->top = L->top + LUA_MINSTACK; 308 lua_assert(ci->top <= L->stack_last); 309 L->allowhook = 0; /* cannot call hooks inside a hook */ 310 ci->callstatus |= CIST_HOOKED; 311 lua_unlock(L); 312 (*hook)(L, &ar); 313 lua_lock(L); 314 lua_assert(!L->allowhook); 315 L->allowhook = 1; 316 ci->top = restorestack(L, ci_top); 317 L->top = restorestack(L, top); 318 ci->callstatus &= ~CIST_HOOKED; 319 } 320 } 321 322 323 static void callhook (lua_State *L, CallInfo *ci) { 324 int hook = LUA_HOOKCALL; 325 ci->u.l.savedpc++; /* hooks assume 'pc' is already incremented */ 326 if (isLua(ci->previous) && 327 GET_OPCODE(*(ci->previous->u.l.savedpc - 1)) == OP_TAILCALL) { 328 ci->callstatus |= CIST_TAIL; 329 hook = LUA_HOOKTAILCALL; 330 } 331 luaD_hook(L, hook, -1); 332 ci->u.l.savedpc--; /* correct 'pc' */ 333 } 334 335 336 static StkId adjust_varargs (lua_State *L, Proto *p, int actual) { 337 int i; 338 int nfixargs = p->numparams; 339 StkId base, fixed; 340 lua_assert(actual >= nfixargs); 341 /* move fixed parameters to final position */ 342 luaD_checkstack(L, p->maxstacksize); /* check again for new 'base' */ 343 fixed = L->top - actual; /* first fixed argument */ 344 base = L->top; /* final position of first argument */ 345 for (i=0; i<nfixargs; i++) { 346 setobjs2s(L, L->top++, fixed + i); 347 setnilvalue(fixed + i); 348 } 349 return base; 350 } 351 352 353 static StkId tryfuncTM (lua_State *L, StkId func) { 354 const TValue *tm = luaT_gettmbyobj(L, func, TM_CALL); 355 StkId p; 356 ptrdiff_t funcr = savestack(L, func); 357 if (!ttisfunction(tm)) 358 luaG_typeerror(L, func, "call"); 359 /* Open a hole inside the stack at `func' */ 360 for (p = L->top; p > func; p--) setobjs2s(L, p, p-1); 361 incr_top(L); 362 func = restorestack(L, funcr); /* previous call may change stack */ 363 setobj2s(L, func, tm); /* tag method is the new function to be called */ 364 return func; 365 } 366 367 368 369 #define next_ci(L) (L->ci = (L->ci->next ? L->ci->next : luaE_extendCI(L))) 370 371 372 /* 373 ** returns true if function has been executed (C function) 374 */ 375 int luaD_precall (lua_State *L, StkId func, int nresults) { 376 lua_CFunction f; 377 CallInfo *ci; 378 int n; /* number of arguments (Lua) or returns (C) */ 379 ptrdiff_t funcr = savestack(L, func); 380 switch (ttype(func)) { 381 case LUA_TLCF: /* light C function */ 382 f = fvalue(func); 383 goto Cfunc; 384 case LUA_TCCL: { /* C closure */ 385 f = clCvalue(func)->f; 386 Cfunc: 387 luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */ 388 ci = next_ci(L); /* now 'enter' new function */ 389 ci->nresults = nresults; 390 ci->func = restorestack(L, funcr); 391 ci->top = L->top + LUA_MINSTACK; 392 lua_assert(ci->top <= L->stack_last); 393 ci->callstatus = 0; 394 luaC_checkGC(L); /* stack grow uses memory */ 395 if (L->hookmask & LUA_MASKCALL) 396 luaD_hook(L, LUA_HOOKCALL, -1); 397 lua_unlock(L); 398 n = (*f)(L); /* do the actual call */ 399 lua_lock(L); 400 api_checknelems(L, n); 401 luaD_poscall(L, L->top - n); 402 return 1; 403 } 404 case LUA_TLCL: { /* Lua function: prepare its call */ 405 StkId base; 406 Proto *p = clLvalue(func)->p; 407 n = cast_int(L->top - func) - 1; /* number of real arguments */ 408 luaD_checkstack(L, p->maxstacksize + p->numparams); 409 for (; n < p->numparams; n++) 410 setnilvalue(L->top++); /* complete missing arguments */ 411 if (!p->is_vararg) { 412 func = restorestack(L, funcr); 413 base = func + 1; 414 } 415 else { 416 base = adjust_varargs(L, p, n); 417 func = restorestack(L, funcr); /* previous call can change stack */ 418 } 419 ci = next_ci(L); /* now 'enter' new function */ 420 ci->nresults = nresults; 421 ci->func = func; 422 ci->u.l.base = base; 423 ci->top = base + p->maxstacksize; 424 lua_assert(ci->top <= L->stack_last); 425 ci->u.l.savedpc = p->code; /* starting point */ 426 ci->callstatus = CIST_LUA; 427 L->top = ci->top; 428 luaC_checkGC(L); /* stack grow uses memory */ 429 if (L->hookmask & LUA_MASKCALL) 430 callhook(L, ci); 431 return 0; 432 } 433 default: { /* not a function */ 434 func = tryfuncTM(L, func); /* retry with 'function' tag method */ 435 return luaD_precall(L, func, nresults); /* now it must be a function */ 436 } 437 } 438 } 439 440 441 int luaD_poscall (lua_State *L, StkId firstResult) { 442 StkId res; 443 int wanted, i; 444 CallInfo *ci = L->ci; 445 if (L->hookmask & (LUA_MASKRET | LUA_MASKLINE)) { 446 if (L->hookmask & LUA_MASKRET) { 447 ptrdiff_t fr = savestack(L, firstResult); /* hook may change stack */ 448 luaD_hook(L, LUA_HOOKRET, -1); 449 firstResult = restorestack(L, fr); 450 } 451 L->oldpc = ci->previous->u.l.savedpc; /* 'oldpc' for caller function */ 452 } 453 res = ci->func; /* res == final position of 1st result */ 454 wanted = ci->nresults; 455 L->ci = ci = ci->previous; /* back to caller */ 456 /* move results to correct place */ 457 for (i = wanted; i != 0 && firstResult < L->top; i--) 458 setobjs2s(L, res++, firstResult++); 459 while (i-- > 0) 460 setnilvalue(res++); 461 L->top = res; 462 return (wanted - LUA_MULTRET); /* 0 iff wanted == LUA_MULTRET */ 463 } 464 465 466 /* 467 ** Call a function (C or Lua). The function to be called is at *func. 468 ** The arguments are on the stack, right after the function. 469 ** When returns, all the results are on the stack, starting at the original 470 ** function position. 471 */ 472 void luaD_call (lua_State *L, StkId func, int nResults, int allowyield) { 473 if (++L->nCcalls >= LUAI_MAXCCALLS) { 474 if (L->nCcalls == LUAI_MAXCCALLS) 475 luaG_runerror(L, "C stack overflow"); 476 else if (L->nCcalls >= (LUAI_MAXCCALLS + (LUAI_MAXCCALLS>>3))) 477 luaD_throw(L, LUA_ERRERR); /* error while handling stack error */ 478 } 479 intptr_t remaining = stack_remaining(); 480 if (L->runerror == 0 && remaining < LUAI_MINCSTACK) 481 luaG_runerror(L, "C stack overflow"); 482 if (L->runerror != 0 && remaining < LUAI_MINCSTACK / 2) 483 luaD_throw(L, LUA_ERRERR); /* error while handling stack error */ 484 if (!allowyield) L->nny++; 485 if (!luaD_precall(L, func, nResults)) /* is a Lua function? */ 486 luaV_execute(L); /* call it */ 487 if (!allowyield) L->nny--; 488 L->nCcalls--; 489 } 490 491 492 static void finishCcall (lua_State *L) { 493 CallInfo *ci = L->ci; 494 int n; 495 lua_assert(ci->u.c.k != NULL); /* must have a continuation */ 496 lua_assert(L->nny == 0); 497 if (ci->callstatus & CIST_YPCALL) { /* was inside a pcall? */ 498 ci->callstatus &= ~CIST_YPCALL; /* finish 'lua_pcall' */ 499 L->errfunc = ci->u.c.old_errfunc; 500 } 501 /* finish 'lua_callk'/'lua_pcall' */ 502 adjustresults(L, ci->nresults); 503 /* call continuation function */ 504 if (!(ci->callstatus & CIST_STAT)) /* no call status? */ 505 ci->u.c.status = LUA_YIELD; /* 'default' status */ 506 lua_assert(ci->u.c.status != LUA_OK); 507 ci->callstatus = (ci->callstatus & ~(CIST_YPCALL | CIST_STAT)) | CIST_YIELDED; 508 lua_unlock(L); 509 n = (*ci->u.c.k)(L); 510 lua_lock(L); 511 api_checknelems(L, n); 512 /* finish 'luaD_precall' */ 513 luaD_poscall(L, L->top - n); 514 } 515 516 517 static void unroll (lua_State *L, void *ud) { 518 UNUSED(ud); 519 for (;;) { 520 if (L->ci == &L->base_ci) /* stack is empty? */ 521 return; /* coroutine finished normally */ 522 if (!isLua(L->ci)) /* C function? */ 523 finishCcall(L); 524 else { /* Lua function */ 525 luaV_finishOp(L); /* finish interrupted instruction */ 526 luaV_execute(L); /* execute down to higher C 'boundary' */ 527 } 528 } 529 } 530 531 532 /* 533 ** check whether thread has a suspended protected call 534 */ 535 static CallInfo *findpcall (lua_State *L) { 536 CallInfo *ci; 537 for (ci = L->ci; ci != NULL; ci = ci->previous) { /* search for a pcall */ 538 if (ci->callstatus & CIST_YPCALL) 539 return ci; 540 } 541 return NULL; /* no pending pcall */ 542 } 543 544 545 static int recover (lua_State *L, int status) { 546 StkId oldtop; 547 CallInfo *ci = findpcall(L); 548 if (ci == NULL) return 0; /* no recovery point */ 549 /* "finish" luaD_pcall */ 550 oldtop = restorestack(L, ci->extra); 551 luaF_close(L, oldtop); 552 seterrorobj(L, status, oldtop); 553 L->ci = ci; 554 L->allowhook = ci->u.c.old_allowhook; 555 L->nny = 0; /* should be zero to be yieldable */ 556 luaD_shrinkstack(L); 557 L->errfunc = ci->u.c.old_errfunc; 558 ci->callstatus |= CIST_STAT; /* call has error status */ 559 ci->u.c.status = status; /* (here it is) */ 560 return 1; /* continue running the coroutine */ 561 } 562 563 564 /* 565 ** signal an error in the call to 'resume', not in the execution of the 566 ** coroutine itself. (Such errors should not be handled by any coroutine 567 ** error handler and should not kill the coroutine.) 568 */ 569 static l_noret resume_error (lua_State *L, const char *msg, StkId firstArg) { 570 L->top = firstArg; /* remove args from the stack */ 571 setsvalue2s(L, L->top, luaS_new(L, msg)); /* push error message */ 572 api_incr_top(L); 573 luaD_throw(L, -1); /* jump back to 'lua_resume' */ 574 } 575 576 577 /* 578 ** do the work for 'lua_resume' in protected mode 579 */ 580 static void resume_cb (lua_State *L, void *ud) { 581 int nCcalls = L->nCcalls; 582 StkId firstArg = cast(StkId, ud); 583 CallInfo *ci = L->ci; 584 if (nCcalls >= LUAI_MAXCCALLS) 585 resume_error(L, "C stack overflow", firstArg); 586 if (L->status == LUA_OK) { /* may be starting a coroutine */ 587 if (ci != &L->base_ci) /* not in base level? */ 588 resume_error(L, "cannot resume non-suspended coroutine", firstArg); 589 /* coroutine is in base level; start running it */ 590 if (!luaD_precall(L, firstArg - 1, LUA_MULTRET)) /* Lua function? */ 591 luaV_execute(L); /* call it */ 592 } 593 else if (L->status != LUA_YIELD) 594 resume_error(L, "cannot resume dead coroutine", firstArg); 595 else { /* resuming from previous yield */ 596 L->status = LUA_OK; 597 ci->func = restorestack(L, ci->extra); 598 if (isLua(ci)) /* yielded inside a hook? */ 599 luaV_execute(L); /* just continue running Lua code */ 600 else { /* 'common' yield */ 601 if (ci->u.c.k != NULL) { /* does it have a continuation? */ 602 int n; 603 ci->u.c.status = LUA_YIELD; /* 'default' status */ 604 ci->callstatus |= CIST_YIELDED; 605 lua_unlock(L); 606 n = (*ci->u.c.k)(L); /* call continuation */ 607 lua_lock(L); 608 api_checknelems(L, n); 609 firstArg = L->top - n; /* yield results come from continuation */ 610 } 611 luaD_poscall(L, firstArg); /* finish 'luaD_precall' */ 612 } 613 unroll(L, NULL); 614 } 615 lua_assert(nCcalls == L->nCcalls); 616 } 617 618 619 LUA_API int lua_resume (lua_State *L, lua_State *from, int nargs) { 620 int status; 621 int oldnny = L->nny; /* save 'nny' */ 622 lua_lock(L); 623 luai_userstateresume(L, nargs); 624 L->nCcalls = (from) ? from->nCcalls + 1 : 1; 625 L->nny = 0; /* allow yields */ 626 api_checknelems(L, (L->status == LUA_OK) ? nargs + 1 : nargs); 627 status = luaD_rawrunprotected(L, resume_cb, L->top - nargs); 628 if (status == -1) /* error calling 'lua_resume'? */ 629 status = LUA_ERRRUN; 630 else { /* yield or regular error */ 631 while (status != LUA_OK && status != LUA_YIELD) { /* error? */ 632 if (recover(L, status)) /* recover point? */ 633 status = luaD_rawrunprotected(L, unroll, NULL); /* run continuation */ 634 else { /* unrecoverable error */ 635 L->status = cast_byte(status); /* mark thread as `dead' */ 636 seterrorobj(L, status, L->top); 637 L->ci->top = L->top; 638 break; 639 } 640 } 641 lua_assert(status == L->status); 642 } 643 L->nny = oldnny; /* restore 'nny' */ 644 L->nCcalls--; 645 lua_assert(L->nCcalls == ((from) ? from->nCcalls : 0)); 646 lua_unlock(L); 647 return status; 648 } 649 650 651 LUA_API int lua_yieldk (lua_State *L, int nresults, int ctx, lua_CFunction k) { 652 CallInfo *ci = L->ci; 653 luai_userstateyield(L, nresults); 654 lua_lock(L); 655 api_checknelems(L, nresults); 656 if (L->nny > 0) { 657 if (L != G(L)->mainthread) 658 luaG_runerror(L, "attempt to yield across a C-call boundary"); 659 else 660 luaG_runerror(L, "attempt to yield from outside a coroutine"); 661 } 662 L->status = LUA_YIELD; 663 ci->extra = savestack(L, ci->func); /* save current 'func' */ 664 if (isLua(ci)) { /* inside a hook? */ 665 api_check(L, k == NULL, "hooks cannot continue after yielding"); 666 } 667 else { 668 if ((ci->u.c.k = k) != NULL) /* is there a continuation? */ 669 ci->u.c.ctx = ctx; /* save context */ 670 ci->func = L->top - nresults - 1; /* protect stack below results */ 671 luaD_throw(L, LUA_YIELD); 672 } 673 lua_assert(ci->callstatus & CIST_HOOKED); /* must be inside a hook */ 674 lua_unlock(L); 675 return 0; /* return to 'luaD_hook' */ 676 } 677 678 679 int luaD_pcall (lua_State *L, Pfunc func, void *u, 680 ptrdiff_t old_top, ptrdiff_t ef) { 681 int status; 682 CallInfo *old_ci = L->ci; 683 lu_byte old_allowhooks = L->allowhook; 684 unsigned short old_nny = L->nny; 685 ptrdiff_t old_errfunc = L->errfunc; 686 L->errfunc = ef; 687 status = luaD_rawrunprotected(L, func, u); 688 if (status != LUA_OK) { /* an error occurred? */ 689 StkId oldtop = restorestack(L, old_top); 690 luaF_close(L, oldtop); /* close possible pending closures */ 691 seterrorobj(L, status, oldtop); 692 L->ci = old_ci; 693 L->allowhook = old_allowhooks; 694 L->nny = old_nny; 695 luaD_shrinkstack(L); 696 } 697 L->errfunc = old_errfunc; 698 return status; 699 } 700 701 702 703 /* 704 ** Execute a protected parser. 705 */ 706 struct SParser { /* data to `f_parser' */ 707 ZIO *z; 708 Mbuffer buff; /* dynamic structure used by the scanner */ 709 Dyndata dyd; /* dynamic structures used by the parser */ 710 const char *mode; 711 const char *name; 712 }; 713 714 715 static void checkmode (lua_State *L, const char *mode, const char *x) { 716 if (mode && strchr(mode, x[0]) == NULL) { 717 luaO_pushfstring(L, 718 "attempt to load a %s chunk (mode is " LUA_QS ")", x, mode); 719 luaD_throw(L, LUA_ERRSYNTAX); 720 } 721 } 722 723 724 static void f_parser (lua_State *L, void *ud) { 725 int i; 726 Closure *cl; 727 struct SParser *p = cast(struct SParser *, ud); 728 int c = zgetc(p->z); /* read first character */ 729 lua_assert(c != LUA_SIGNATURE[0]); /* binary not supported */ 730 checkmode(L, p->mode, "text"); 731 cl = luaY_parser(L, p->z, &p->buff, &p->dyd, p->name, c); 732 lua_assert(cl->l.nupvalues == cl->l.p->sizeupvalues); 733 for (i = 0; i < cl->l.nupvalues; i++) { /* initialize upvalues */ 734 UpVal *up = luaF_newupval(L); 735 cl->l.upvals[i] = up; 736 luaC_objbarrier(L, cl, up); 737 } 738 } 739 740 741 int luaD_protectedparser (lua_State *L, ZIO *z, const char *name, 742 const char *mode) { 743 struct SParser p; 744 int status; 745 L->nny++; /* cannot yield during parsing */ 746 p.z = z; p.name = name; p.mode = mode; 747 p.dyd.actvar.arr = NULL; p.dyd.actvar.size = 0; 748 p.dyd.gt.arr = NULL; p.dyd.gt.size = 0; 749 p.dyd.label.arr = NULL; p.dyd.label.size = 0; 750 luaZ_initbuffer(L, &p.buff); 751 status = luaD_pcall(L, f_parser, &p, savestack(L, L->top), L->errfunc); 752 luaZ_freebuffer(L, &p.buff); 753 luaM_freearray(L, p.dyd.actvar.arr, p.dyd.actvar.size); 754 luaM_freearray(L, p.dyd.gt.arr, p.dyd.gt.size); 755 luaM_freearray(L, p.dyd.label.arr, p.dyd.label.size); 756 L->nny--; 757 return status; 758 } 759